Lifting jack



April 17, 1928. 1,666,741

, A. H. JOHNSON LIFTING JACK Filed March 22. 1926 INVENTOR Alfred H.John5on Patented Apr. 17, 1928 UNITED STATES PATENT OFFICE.

ALFRED H. JOHNSON,

The main provide an OF NILES, MICHIGAN, ASSIGNOR TO NATIONAL STANDARD COMPANY, OF NILES, MICHIGAN.

. LIFTING JACK..

Application filed March 22, 1926. Serial No. 96,555.

object of this invention is to improved lifting jack of the screw type which is very compact when collapsed and of considerable height when ex- 5 tended, and one in which the parts are arranged so that the lifting members or sections are suc vA further cessively extended and collapsed. object is to provide a jack having these advantages in which the parts are so formed a paratively s weight, and

nd arranged that they are comimple in structure and light in not likely to be placed under undue stress in use or operation.

- Objects p ertaining to details and economice of construction and operation of my lnvention will definitely appear from the detailed description to follow.

The invention is clearly defined and pointed out in the claims.

A structure embodying the features of my invention is plication,

clearly illustrated in the accomof this ap- Fig. 1 1s a side view of my improved jack,

the driving away.

Fig. 2 is cal section on a as of Fig Fig. 3 is In the shaft or crank being broken a detail View partially in vertiline corresponding to line s. 1 and 3.

a horizontal section on a line to line 3-3 of Fig. 2.

proved jack comprises a standard or base section 1 ha gitudinal bore 3 therein.

base orfoot 2 and a lonving a At one side of this bore is a shallow groove 4 extending the length of the bore and having inclined in- Wardly diverging sides 5.

The tubular lifting member or screw 6 is adapted to telescope within the standard and is supported thereon by means of the nut 7.

A thrust ball bearing designated generally by the numeral 8 is interposed between the nut and the has a bevele end of the standard. This nut d gear 9 thereon, the gear being formed integrally with the nut in the structure illustrated.

At the upper end of the standard is a yokelike bracket 10 having a collar-like part 11 alined with the bore of the standard, the nut being interposed between the bearing and this bracket so that vertical movement of the nut is prevented. .The nut is driven from the pinion 1 13 provided 2 which mounted in a bearing thereforin the bracket 10. The

with a longitudinal driving shaft or crank 14 is conventionally indicated in Fig. 1.

A split ring 15 engaged around the upper end of the member 6 limits the downward travel, this ring engaging the yoke and acting as a stop. At the lower end of the lifting member 6 I mount a tubular holder 16 for the pin 17, a spring 18 being arranged to yieldingly urge engagement with the groove 4. As the nut is rotated the engagement of the pin with the groove yieldingly holds the lifting member against rotation between the limits of its travel, the pin yielding, however, when undue stress is applied to turn the lifting member. This pin also coacts with the bearing 8 limiting the upward travel of the lifting member 6.

When the limits of travel of the lifting member are reached the pin yields to permit the turning of the lifting member. The second lifting member or screw 19 is externally threaded to engage the internally threaded part 20 of the lifting member 6. This screw 19 is provided with a head 21 adapted to engage the work.

The screw or lifting member 19 is free to rotate until it engages the work when it is held against rotation and it is thereafter elevated or lowered by the rotation of the lifting member 6 which acts as a driving nut.

My improved lifting jack is very simple and compact in structure, the parts are easily formed and compact in structure, the parts are easily formed andassembled, and at the same time they are durable and are not likely to be injured in use.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a lifting jack, the combination of a; standard having a shallow longitudinal bore groove having beveled edges opening thereto, a nut mounted on said standard, means for driving said nut, a tubuto rotate at the ends of its travel,and a sec- 0nd lifting member'arranged in said tubular lifting member and having threaded engagement therewithand having a work engaging head at its upper end.

2. In a lifting jack, the combination of a standard having a shallow longitudinal bore having a longitudinal guide means with beveled edges, a nut mounted on said standard, means for driving said nut, a tubular lift- 10 ing member disposed in said standard and externally threaded to coact with said nut,

means for limiting the travel of said lifting member within said standard, a yielding member on said lifting member adapted to .yieldably engage said guide means, and a second lifting screw disposed within and having threaded engagement with said tubular lifting member.

In witness whereof I have hereunto set myhand.

' ALFRED JOHNSON. 

